A study conducted at the University of Cambridge in the UK, involving 238 teenagers between the ages of 15 and 18 years, focused on investigating how GENES AND ENVIRONMENT INTERACT and in what ways this interaction increases or decreases an individual’s chances of being. diagnosed with depression in later life.

In the study, the teenagers were put into six different groups; the group they were placed in was determined by two factors :

1) Whether or not they had experienced significant childhood trauma (e.g. exposure to family arguments, stress and other trauma) prior to the age of 6 years

2) Their particular type of genetic variation in relation to a specific gene involved in the production of serotonin in the brain (serotonin is a neurotransmitter – a sort of chemical messenger which helps cells in the brain communicate with one another – and affects our moods and emotional state).The teenagers all had one of the following 3 types of genetic variation:

a) SS (two short versions of gene)

b) SL (one short and one long version of gene)

c) LL (two long versions of gene)

RESULTS :

Those who had been exposed to trauma before the age of 6 years were more likely to develop depression later on BUT ONLY IF THEY ALSO HAD A GENETIC VULNERABILITY (genetic vulnerability, the study found, was due to having the SS variation or SL variation of the gene, represented above by categories ‘a’ and ‘b’).

Specifically, it was found that exposure to discord between parents and/or neglectled to the individual :

iv) being more affected by the emotional tone of other people’s voices.

According to the study, these four factors, in turn, make it more likely that the individual will later be diagnosed with depression.

CONCLUSION:

Having both the SS or SL variation of the gene AND experiencing early trauma is associated with a higher probability of being diagnosed with depression later on in life.

HOWEVER: having the LL variation of the gene and experiencing early trauma is NOT associated with a higher probability of being diagnosed with depression later on.

THEREFORE: having the SS or SL variation of the gene makes the individual MORE VULNERABLE TO THE EFFECTS OF EARLY TRAUMA, thus making it more likely that the s/he will eventually be diagnosed with depression, whereas, HAVING THE LL VARIATION OF THE GENE SEEMS TO PROTECT THE INDIVIDUAL FROM THE EFFECTS OF EARLY TRAUMA.

It may be inferred, then, that neither early trauma alone, nor genetic vulnerability alone, are sufficient to make it more likely the individual will be diagnosed with depression. It seems, instead, it is how the relevant genes and early life experiences INTERACT that determines the likelihood that a particular individual will develop depression.

N.B. It should be noted that research such as that described above is at a relatively early stage and more studies need to be carried out in order to clarify, build upon and refine these findings.

How Genes And Childhood Trauma Interact :

Starting with the top row of the diagram we can see that a person’s genes and childhood environment interact to produce the person’s phenotype (a phenotype refers to the characteristics a person develops as a result of the interaction between his/her genes and environment). The phenotype is also affected (as we can see on the second row) by the degree of stress the person experiences in childhood, but, also, by the amount of social/emotional support s/he receives.

For example, high stress and low support would clearly be more likely to lead to high vulnerability (see third row) to psychopathology such as depression, anxiety, PTSD and substance abuse (also shown on third row) and physiopathology such as poor immunity, problems with metabolism and cardiovascular disease (this, too, is represented on the third row).

The combination of factors shown on the diagram then determine how well or badly the individual is able to cope with life in general (represented on the diagram by ‘long-term maladaption/adaption’ on the fourth and final row).

MORE ABOUT ENVIRONMENTAL EFFECTS ON DNA :

Recent studies have shown that childhood trauma can actually change the structure of DNA in the person who has suffered it and consequently alter how these genes work (it has been known for some time that how genes express themselves is influenced by their interaction with the environment).

Animal studies support this finding: in rats it has been shown that QUALITY OF MATERNAL CARE HAS A LARGE EFFECT ON GENES RESPONSIBLE FOR THE STRESS RESPONSE IN OFFSPRING:

Indeed, there is a growing body of evidence that psychological abuse of children has BIOLOGICAL effects. Research suggests that the effects of abuse on the child’s DNA lowers their resistance to stress. This effect can persist throughout life and increases the suicide risk of the individual.

It is thought that trauma/abuse in early childhood (before the age of six) can have a particularly damaging effect on the DNA which controls the individual’s stress response.

(For those that are interested, environment affects DNA (and thus how it expresses itself) by punctuating it with what are technically known as EPIGENETIC MARKERS. It follows from this that the function of DNA is not permanently fixed from birth, but can be altered by its interaction with the environment).

The good news is, however, that the adverse effects on DNA caused by childhood trauma can be reversed in adult life by appropriate interventions. Key to these are the replacement of the traumatic environment with one which is supportive, loving, stable, safe and relatively stress-free. This is because just as traumatic environments can leave harmful epigenetic marks, good environments, over time, can reverse this effect.

CHILDHOOD TRAUMA, GENES AND DEPRESSION :

Just as trauma can affect genes, pre-existing genes can affect the impact trauma is likely to have on us; it is, to this extent, a two-way street then. It has already been stated in previous posts how exposure to trauma in childhood can lead to psychological problems such as clinical depression; studies now show that the risk becomes even greater if the sufferer of childhood trauma has a particular genetic make-up making him or her more vulnerable to the effects of stress:

So: children who are genetically predisposed to being particularly vulnerable to stress will typically be more adversely affected by the childhood trauma than those children who do not have the genetic vulnerability. THIS HELPS TO EXPLAIN WHY TWO CHILDREN WHO SUFFER SIMILAR TRAUMA MAY BE AFFECTED QUITE DIFFERENTLY FROM ONE ANOTHER.

Further study has shown that the children with the particular genetic variation are MORE SENSITIVE TO THE ENVIRONMENT AROUND THEM (they process emotional information differently) than children without the variation. The genes involved are responsible for the production of SEROTONIN (a chemical affecting mood, also known as a neurotransmitter) in the brain.

DISCORD BETWEEN PARENTS and NEGLECT (again, especially if the child is under six) have specifically been linked to the child developing HIGH EMOTIONAL SENSITIVITY and a greater susceptibility to stress. Again, if the child has the genetic variation making him or her particularly vulnerable, the adverse effects of the discord or neglect will be increase such vulnerability.

The research producing such findings as illustrated above is still in a relatively early stage and future research is likely to help clarify the complex interactions between our genes and how childhood trauma affects us.

Childhood Trauma Can Affect Our Genes In Such A Way That Our Ability To Cope With Stress Is Greatly Diminished :

A study led by Seth Pollak (University of Wisconsin) suggests that abuse can adversely affect children at a cellular level, including the turning off or on of particular genes (this phenomenon is called EPIGENETICS – the modification of genes by the environment).

The study involved examining the DNA of children who had been identified (by Child Protection Services) as having been abused. Blood samples were taken from each of the children in order to enable this analysis.

It was found that, in each of the children, the same, specific gene (NR3C1) had been damaged. When this gene is working properly, it helps the child to manage stress (i.e. to calm down in a timely fashion after having been upset). It does this, when healthy, by preventing too much cortisol (a major stress hormone) from building up in the body.

However, in the abused children, the damage to this gene means that, under stress, too much cortisol DOES build up in their body. The effect is that the children are unable to calm themselves in the way non-abused children are able to.

This damage to the gene can result, therefore, in the child being in a constant state of hypervigilance (i.e. perpetually tense and in a state of ‘red-alert’). As a result, the child is likely to perceive threats where, objectively speaking, they do not exist, and frequently become preemptively aggressive and very easily enraged.

Additionally, such children are more likely to suffer from depression and anxiety, to find any kind of significant change difficult to cope with, and, later in life, to develop physical problems such as diabetes 2 and heart disease.

THE GOOD NEWS :

Studies of rodents have found that rat pups that are abused in early life also incur damage to the same (NR3C1) gene that, when operating correctly, helps them regulate stress (the same as it does in humans, as described above).

The good news, though, is that it has been found that when these rats are removed from their abusive environments and returned to nurturing mothers, the damage to the NR3C1 gene is reversed.

By extrapolation, this suggests the same reversal of damage may be possible in humans. Unfortunately, however, the necessary research to establish whether or not this is the case has not yet (at the time of writing) been carried out.

Childhood Trauma, Life Events And Depression :

A recent research study, carried out by Wiersma et. al, focused on possible causes of chronic depression (chronic depression is long-lasting depression which has been continuous for two years or more – 20% of those with major depression suffer from this chronic form of it.

When major depression is also chronic, it is particularly serious; this is because those individuals who are chronically depressed are more likely to be hospitalized and more likely to commit suicide than those who suffer from episodic depression) found that the GREATEST RISK FACTOR LINKED TO THE DEVELOPMENT OF LATER ADULT CHRONIC DEPRESSION WAS CHILDHOOD TRAUMA.

The study ran over a time period of 8 years and involved 1230 participants (two thirds of whom were female). Amongst other factors, the study sought to determine the link between adult chronic depression and:

– those who had experienced childhood trauma (physical/emotional/sexual abuse) were significantly more likely to suffer from chronic depression compared to those who had not experienced childhood trauma

however :

– Childhood Life Experiences which, according to self-reports from the participants, had NOT involved significant trauma, did NOT significantly increase the likelihood of the later development of adult chronic depression.

OTHER RESULTS FROM THE STUDY :

– the more frequent the experiences of childhood trauma were, the greater was the risk that the individual would go on to develop adult chronic depression

– those who had suffered most severely from childhood trauma were 3 times more likely to go on to develop adult chronic depression compared to those who had not suffered significant trauma. Furthermore, they were found to be at significant increased risk of developing co-morbid psychiatric conditions, such as anxiety. Finally, too, it was found that, on average, the age of onset of their depressive condition was earlier.

CONCLUSIONS :

– these findings are consistent with previous research findings

– it can be inferred from the results that IT IS NOT THE LIFE|EVENTS, PER SE, WHICH INCREASE THE CHANCES OF THE LATER DEVELOPMENT OF ADULT CHRONIC DEPRESSION; RATHER, IT IS THE QUALITY OF THE CHILD’S HOME ENVIRONMENT WHICH IS CRUCIAL.

IMPLICATIONS FOR THE TREATMENT OF DEPRESSION :

We are able to infer from the above findings that it is quite possible that :

a) depression associated with childhood trauma

and

b) depression NOT associated with childhood trauma

may react differently to particular types of treatment.

For example, studies extending on the one described above suggest that depression associated with childhood trauma is more likely to respond well to psychotherapy rather than psycho-pharmacology (treatment with drugs). Therefore, clinicians need to be aware of whether their depressed patients experienced childhood trauma, in order that a more informed decision about appropriate treatment may be taken.

Can Facing Up To Our Childhood Trauma Help Alleviate Our Depression?

Alice Miller (1923 – 2010), the world renowned psychologist and expert on the damage that can be done to individuals during their childhood, and its implications for their adult lives, states, unequivocally, that, if we are suffering from depression linked to our childhood, traumatic experiences, it is imperative that we start to understand, and to process mentally, the harm that was done to us when we were children.

Miller states that one reason we may not accept and acknowledge our childhood suffering and the responsibility our parents have for having inflicted this, or for having failed to protect us from it, is that we may still be idealising our parents. She goes on to say that it is necessary for us to overcome this psychological defence mechanism and attempt to recall, as fully as possible (in a therapeutically safe environment) how we were badly treated as children and how this made us feel at the time.

Above : Alice Miller

Only by getting in touch with these feelings, Miller explains, and then by acknowledging the psychological suffering our parents caused us when we were young and helpless, and, furthermore, by not being afraid to healthily express our pent up feelings of anger and rage, can we finally, perhaps after decades, free ourselves from our depressive state.

Putting it simply, Miller is of the view that by denying we were ill-treated, out of misguided loyalty to our parents, and by continuing to repress the rage that this treatment caused, we perpetuate our psychological illness. We must, then, according to Miller, unblock our original feelings.

In order to help us to get back in touch with these repressed feelings, we should ask ourselves if our parents would treat us now as they did then. If the answer to this question is ‘no’, Miller explains, then it begs the question : ‘were they taking advantage of our helplessness, vulnerability and dependency to behave as they did, at the time, with impunity?

As well as getting in touch with our repressed rage, Miller counsels us, we should also try to reconnect with the fear and deep sadness we felt as children, as well as with our childhood sense of helplessness and isolation. Then, by processing these authentic, original feelings, cathartically and under the supervision and with the support of a suitably qualified and experienced psychotherapist, can we recover our mental health and equilibrium.

NB. Those who share Miller’s views should only undertake such a process under the care and supervision of a properly qualified expert in the field.

Childhood Trauma, Depression And Learned Helplessness :

If we suffered a traumatic childhood in which we felt powerless to change our situation for the better, we may have become conditioned to believe that there is no point in trying to improve our situation in life as any such attempt will inevitably be doomed to failure. Such a state of mind, one of the hallmarks of clinical depression, has been termed ‘learned helplessness’ by psychologists. If we are suffering from learned helplessness, we will lack motivation to create positive change even when it is clearly possible to do so from an objective perspective.

The following experiment, involving dogs, helps to illustrate precisely what psychologists mean by the condition of learned helplessness. It is a controversial experiment which is ethically questionable and I do not think I would feel comfortable carrying out such a research activity myself. However, here are the findings :

PHASE 1 OF EXPERIMENT :

The experiment, part of a research study by Martin Seligman, was carried out in the 1960s and involved two sets of dogs. Both sets of dogs were given electric shocks ; however :

– one group of dogs could stop the pain by learning to press a lever

– the other group of dogs could not escape the pain whatever they did

PHASE 2 OF EXPERIMENT :

After this unpleasant experience, BOTH groups of dogs were placed in shuttle box with two sides separated by a short barrier. Again, electric shocks were applied through the floor in the cage. This time, however, IT WAS POSSIBLE FOR BOTH SETS OF DOGS TO ESCAPE THE PAIN by jumping over the short barrier to the other (safe) side of the box.

RESULTS :

– the first group of dogs (who had control in the first phase of the experiment by being able to press the lever to stop the shocks) learned to avoid the pain by jumping the barrier in phase 2.

HOWEVER :

– the second set of dogs (who had no control over the electric shocks in the first phase of the experiment) failed to avoid the punishment (they did not learn they could do so by jumping the barrier) in phase 2.

It is thought, in the same way, that if as children we have been in traumatic situations over extended time periods that we were unable to escape, as adults we might become, like the second group of dogs in the experiment, despondent, depressed and unable to try to help ourselves.

However, also like the second set of dogs in the experiment, we may falsely believe we can’t help ourselves (due to our past experiences) when, in fact, we can – it can be our depressed and helpless frame of mind, formed in our childhoods, that creates the illusion that there is no way out for us when, in fact, there is.

Behavioral Activation :

One of the hallmarks of serious, clinical depression is reduced ability to perform everyday tasks and activities. Again, in my own case, I was often confined to my bed for much of the day, stopped washing, rarely shaved and stopped brushing my teeth.

I know, therefore, that when very ill with depression, even basic tasks can feel impossible to undertake – indeed, even contemplating having to carry them out can, when one is so ill, create severe anxiety and distress. For those who have not experienced clinical depression, this is almost impossible to imagine or comprehend; such lack of empathy leaves one feeling devastatingly alone and terrifyingly emotionally imprisoned, compounding the problem.

Sadly, this loss of ability to carry out everyday tasks and activities tends to perpetuate and even intensify one’s depressive state, thus creating a vicious cycle.

Above : Avoidant behaviour can set off a vicious circle, whilst behavioural reactivation can set off a virtuous circle.

Behavioral Activation :

The psychologist Lewiston has carried out research showing how, by reactivating the behaviours we used to carry out before severe depressive illness struck, we can alleviate our depressive symptoms, or, indeed, rid ourselves of the condition entirely.

Lewiston suggests changing our behaviors may be more effective in treating depression even than changing our thinking style (as occurs in cognitive therapy). In other words, he postulates that:

Behavior Therapy (changing the way we behave)

may be a more effective way of treating depression than:

Cognitive Therapy (changing the way we think)

In order to test this hypothesis, Lewiston carried out the following research study:

b) Then, in relation to list, set goals s/he would ideally achieve. For example :

– socialize as much as before the illness struck

– go to gym for an hour, every other day

– limit self to eight hours a day in bed

– keep house reasonably clean

– care for self in same way as prior to becoming ill

Once these goals have been identified, it is necessary to undertake behaviours that help one achieve them.

Now, clearly, achieving all these goals cannot happen immediately!

Therefore, it is usually necessary to take small steps. For example, if trying to attain the goal of going to the gym, for an hour, every other day, one may start off by going to the gym for twenty minutes once per week, then very gradually increase this rate.

The importance of adjusting our behavior positively and increasing our activity levels to help improve our mood seems hard to overstate. Even by starting with tiny steps, a powerfully therapeutic virtuous cycle may be set in motion.